<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <!--页内样式-->
    <script style="text/javascript">
//    alert('hellow world');
        console.log('哈哈')
        console.log('哈哈')
        console.log('哈哈')

    </script>
</head>
<body>

    <button onclick="alert('9999')">百度一下</button>

</body>
</html>